The present invention relates to tip turning apparatus for cigarettes and analogous rod-shaped articles. More particularly, the invention relates to improvements in apparatus of the type wherein rod-shaped articles forming one of two rows of parallel articles are inverted end-for-end and placed between neighboring articles of the other row. The need for such manipulation of rod-shaped articles arises, for example, in machines for the making of filter cigarettes, cigars or cigarillos. As a rule, a filter tipping machine produces articles of double unit length, and each such article is thereupon severed midway between its ends to yield a pair of discrete articles of unit length whose filter tips are adjacent to each other. Prior to introduction of articles into the magazine of a packing machine, one article of each pair must be turned end-for-end so that the filter tips of all articles face in the same direction. Such tip turning or inversion is further necessary prior to transport of articles through one or more testing stations wherein the tobacco-containing ends of articles are monitored for firmness and the defective articles (i.e., those wherein the tobacco-containing ends are too firm or contain insufficient quantities of tobacco) are segregated from satisfactory articles.
Commonly owned German Pat. No. 1,178,756 discloses a tip turning apparatus wherein a rotary inverting conveyor carries two rows of flutes. The flutes of one row are turnable about axes which do not extend exactly radially of the conveyor and are laterally offset with respect to the axes of cigarettes in such flutes. The flutes of the other row are fixedly secured to the conveyor. The cigarettes to be tip turned are introduced into successive flutes of the one row and the respective flutes are thereupon rotated through 180.degree. to invert the cigarettes therein and to place the inverted cigarettes between the cigarettes in the flutes of the other row. The axes about which the flutes of the one row are caused to turn are located in a common plane which is normal to the axis of the conveyor.
The cigarettes which leave the conveyor are deposited on an endless belt. This renders it possible to transport the cigarettes in the other row of flutes at a first distance from the axis of the conveyor and to transport the cigarettes in the one row of flutes at a greater second distance from the conveyor axis. Such arrangement of flutes is necessary in order to insure that the flutes of the other row (and the cigarettes therein) cannot interfere with tip turning of cigarettes in the flutes of the one row.
A drawback of the just described apparatus is that the cigarettes on the aforementioned endless belt are not exactly parallel to each other (because the inverted cigarettes normally move through a shorter distance during transfer from the conveyor onto the belt than the non-inverted cigarettes). Therefore, the patented apparatus must be provided with auxiliary equipment which reorients certain cigarettes on the belt. Moreover, the cigarettes on the belt are staggered, as considered in the axial direction of the cigarettes, so that they must be caused to move between two stationary cams which shift each next-following cigarette axially into accurate register with the preceding cigarette. Such manipulation necessitates additional space and the cams are likely to damage or deface the ends of cigarettes.
Another drawback of the patented apparatus is that it cannot transfer the row consisting of inverted and non-inverted cigarettes directly into the flutes of a rotary drum-shaped conveyor, for example, into the flutes of a drum which is used to transport filter cigarettes through the testing station of a filter tipping machine. The cigarettes at the testing station are examined for the integrity of their wrappers and/or the quality of the tobacco-containing ends. In the patented apparatus, the cigarettes must be transferred onto the aforementioned belt prior to transfer onto a drum-shaped rotary conveyor.